SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c8cba04388161f067497e8ac95f291c2da8e98f928dc24455464b982138ff65' 
  AND token = 'KGAqqLQcb22k75CtON5jGDKDm13o0NNXL/X69b1fRHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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