SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8aa8360f0837f3049d0978e268b144d2d723c9527b203cc937ae7ba75226e6c' 
  AND token = 'i57qEJfGqjTmA3dDX8SSxFvy1er6mW7s3mU3wM1ZM5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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