SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8257045f94769fdad74fbeb4044c568077181cdfcff19403eda588fbc35745e7' 
  AND token = 'npRvn/IiVcE+xmubF2Bb/EhbHagN20LED79tdZrofoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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