SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2dfa0b1868237a2856d252406ab4f90d9fc22801383722c882cf33837d38895d' 
  AND token = 'x+GssF+PiorJ5dMe0s3uOH3mbxTN5SgrxGgdpRseG/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}