SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5aa915b7085145f1067a838622728150d0931de67a892d5b4b0aad8b7a33c9c2' 
  AND token = 'PMCebTQfLdu4udzpz4a1j44sQFYnBco6PX+cn6YIi88=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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