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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03c7ecd848844eca2ea679092e838a364b2a0b217c1a58be505582506e8abe33' 
  AND token = 'A6BRIeDy4T5LnnZPFnXyPsK/LZp39YI9j5s1/LrqMeM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}