SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '444f9d4016fcaf32cace5065f395fbf34de660cddcdaca785c58c53040c9c81c' 
  AND token = 'yblalUjrlcdIU1Ui0jrGjk1iGfpaNDV4w0NWvVEoqiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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