SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a7f34aa2d690878253fa0527fa46f3fb6fb3638ace7e4a53c6b98eca392f183' 
  AND token = 'AS1LacmOZRoQbXghnA2YPNOTcBXXdNqLlizqVbS3dak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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