SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8426447d5d1f374cc6b997f02ec6b96edc672a535e409bd251b3612f8cca978' 
  AND token = 'KoJmk4vghyvk1AYDQqZxh/L3tXvPJS4I3q5KC9+rxN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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