SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac617130aab858446015064fff23ecc5d2896dd8bd4a8dcfe2289761d10dd48d' 
  AND token = '5qvR2JVgG0rLe9jRpNImjaW7WKKhj/fw0T3K1SPZgGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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