SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f85c1d54afc7caa1337fc2c14e61b2f26786f05d353d5890a29c59b7f4f9f303' 
  AND token = 'I+zuLKjajnTjDaEVbibQARotDLCwTqvDowQYCrZvfUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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