SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '449400697c4261154ca6b2ffd44aa286cae7d2aa837dcf21193603e9cbd15b43' 
  AND token = 'Ky6ROQR8oPZ0UVBpgKp5MTn8ZpvVAejqLuKb2HQBHrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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