SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b77bce32d21a0bfb66498718998f32bda0a36296a05add3cf94e7f4e663f35b' 
  AND token = 'eNElu/m7hNFf1do41JDKER+Gw2mG02CnGqV/JZWcQDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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