SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc0b0170e1943a6132dd98cc313801c6af8b4125f3a90b80ee60587647999b37' 
  AND token = 'fI9bZg5sheGkdkamSNC4sCDpxURelwgG7IJopqalp0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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