SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77eb4b8291c46567dd34d5d3b3ae9dd59027c1ea7beefe568527ee5c7fc0fb46' 
  AND token = 'JWf2R1yzLkWUXI6dgT7jEDXeJiKOfD9E/g5PJaFXc1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}