SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '575c76daa9184a40e09384856e5b3c712d51abefd94b992650571679bd34a0d6' 
  AND token = 'nEF55RWtOXcS2cQ9o/98aNOkJIsnSTFdWjqjVRu2xLo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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