SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1268183ef49ea2b6ebf414c1c911d6d629bd8dffafddd900953e914214a8204' 
  AND token = 'jpoCJX2zgNUQipbVKw8oNrvBExHbQag7tG/tTZupYbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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