SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3f7ad351d0a5d7c4d9c9eced151534ccf8e4f98e6b5b84f112d80913db6510a' 
  AND token = 'vaH3PG7AIzuGCKNLG3Io5tC9LUOVARBLp2Fbx9xR1NE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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