SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16e36b5aba591591c8143b511fd84bc3eca77d05c64d5070882f3be05c6512b3' 
  AND token = 'ZNeOBRaPiA56QKL+mbrdmeFAWD8rBU5++M+yliPdw7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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