SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '993b5b46c6675f77fecdb89668deb4383b54e59a80717ec3a63e7beeb9c9c2d8' 
  AND token = 'cXXH+l3aavUHdYR1cVF7oyOmGKVSpylFLRW4vsXKwV4=' 
  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"
    }
  }
}