SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '552737e3c1299cd580dbbe40bbc4d5c51abe476159b3d009796c0ebde860b1b3' 
  AND token = 'HviXGBaPBg3/Kg9C8pEHNIKWmP3Uru0N48vxJjqo7QA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}