SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c78fed2c404b46d195e7521c8883ef9ae4e68478bcbd77ba444f13aa7646b2b0' 
  AND token = 'lMpkHnLePXoBG9wl1BFXlQDzYq1+GLqeDUCPJOXSG9s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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