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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65a4c1d8af03ca1ecffd61db30490fd44e382cb436edb9eed4d2042441fe5bac' 
  AND token = 'L+Ss+8VGJOY9Xq+4KYz4WUERsaPWr0gjeMGbxQTtN7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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