SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd41c8b94ada6825537b155f70abf835a0f9dc0bc7a21dd19f2bc79d859f634aa' 
  AND token = 'IdDE4WjVlG6glWUnkE8SvWOrk8HnimmGTJZ0/0kgqws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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