SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47e3bebdda41b77bbe243240a8d690fe67b67b99902190f8e56316c6851496a0' 
  AND token = 'ohonOqrZjCE/y25tCK2NoRU+zVd+tjyoUYvklKP/zB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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