SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebc77f4028894ae2610dd86d4ff83d8fc02eac330656d7d77f6a09d08b5bca41' 
  AND token = 'szqnHBzN/B0AZcNPzPs1FjRsxgTBJm/1B//G7fh3A8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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