SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03c621d310dcd9a2f9d33b672c3636d915a2169a700cb86989db36edb98d3371' 
  AND token = 'wtWBMoTMWeQLI3YCpRpEni+9FMpo+pcp6S6e1W7G2uI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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