SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84cfda5769c72ceea848535660aeb91bfc3e04a893df098176fc616426f9458e' 
  AND token = 'R4rSwaxaTuEaBp0fzm+Fq06IYtWF5RqDmVU4nbCkvjs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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