SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd057c28c5a2139e26f431eae47436b485b2e6dec3117fa26dfbf5755f6d4a93d' 
  AND token = 'hMxfmgMzj74XJlEZVY/hZZOoiM0LZFs7jSQJ0JdmzLI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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