SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2c39387444631ff190d93c8d51aab8f4629ea862a41f6cb954d341bdd72459e' 
  AND token = 'N37CPTeBVsQhOh3LOrGyYl8GgWgH+w/TugZB+L2pq38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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