SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df32bb1220460846ac7094dd7fc7cf5aa03ea6223118378ec1fffa7ee00ab00c' 
  AND token = 'j8bsNAH/C93kg4lgMs73PpaxppaA49rTpWppFhatLSo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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