SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b2cf4b4cc06eb86b54f5f3a11a50a923d167641f8f400946f38ac3cef702814' 
  AND token = 'dzM82koDaVFqqMx1HfXsm9PC6XAK9IGv7ig/GecxWws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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