SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc775b688ccd385a12722344d14d7eb666478c7115abbeaec8a3549b400a44df' 
  AND token = '6hrJFwSD7JreXIAgM8rLNG6WC26ckuXasduztE8S+r0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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