SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '248f2872a90f63ff9cb6100dd40fac836d426a4c1cb33371009d315a026a9a94' 
  AND token = 'zb6+/FYIzt1/y9sZhiPtKlvUdZXlOrYg4BMfEGDZgfg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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