SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea494168fe10043b358fb00b2ef64018275cef9c8cf610779986dfce3bebbe9e' 
  AND token = '7XGPdihTtFLXmaasyecOMKoS648bRhLdIPaciuhIibc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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