SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5610a9d4c319e40d000dbd0b09caf2f0559a66b89f1385728df401caafecfc06' 
  AND token = 'c2szRwa8yNiJ/gicssvSK1S4oJbc0S5ERm8MY7VSVNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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