SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0804c28b5d720ab219fc460fd017422c1a3e2bec68a0ecc382d1299c6162156' 
  AND token = 'EBDjZ5vviFN3jB8+jd6nBqA+kvy37ae/sWOUd9XN4R4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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