SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1eac56a764019f90a5c89718727fdd600accab735118089de54b21e0cde0c8d' 
  AND token = 'XUf0Vnkx9JJxHsoiptX2VZFrPT5Jsi99Xf+DWTlzymk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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