SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55b3f3258acbf1ebe9aed93d7bb39e22bd99459473def46212ef357843c51a72' 
  AND token = 'EgEwacgvssUPSmTuBqSlOJwQQEZwG5IHv/8WC5FyVbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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