SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66bf44f4ca2d937f06aa4632b67eaab0331196e1c354b57ce04a8e8e8db01f5f' 
  AND token = 'msbqzgxnv2xShQ/jkUYXtxPwYyCkwaZYCG5Gp2wdkMc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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