SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '68c1f971ecfc548c4d185b2c3e438e3d9cdd91a5615b6b7a8f7c6bfce37f1e49' 
  AND token = 'zY/+234nPbZBuul7OphSGe7ICTd3X8/D+4+4mRPZGMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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