SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ce702ffb7d6e7d36a39011c4967fb69334f6fcba07033383b8b1a2cefe98f4d' 
  AND token = 'QmqnzVvmzqsbj5NjgK1CGU/aK2h+SlGwspsM6L3NitY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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