SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc2704d7e64e1bddc83d6b06adbd52206b2491460c4d2a6f156906038cc1667b' 
  AND token = 'CdUt2OgfnY9kvMCIgVy7y9kpryoBrCFCqFE4gns+714=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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