SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'faa68466ee5fdb50d08b85aec47a2499f2cc668db75dd0ae261e4f74deaa4968' 
  AND token = 'OMtfageq+QTxz3HpK8Wgjp2Ypr4vOXmWVTbKSS52LfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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