SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '320cbc944e4300c1dc02a740723c373297f3c89be975c871f38b0d98f3b9d625' 
  AND token = 'IgtlG/IujhIVSQ0EKsnxPSFjDL3PrxHWA2DhGMgpGcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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