SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b61c11dd7ff06ddd1c4233e90996c102d80aca0cdf41e039884f2e3fdf602d31' 
  AND token = '2GJ2qzRlKI4faYvzMNcH65CMHxbFax0yfqcGYfuT62E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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