SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1112f38bd161373daeaf0a11811accda929ffb6f865840c0362bacfd854bdb56' 
  AND token = 'D6HC7rVi2BbLuxTSRXXBwqO46HfS1awinXxCTxzvJd0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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