SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c42f71fc74d3053f3d55ea660dc60a4f254e22e495982e3258a5e846d7913df7' 
  AND token = 'ON938+CuiE3iyjpPkfQcLokJk6Ko2ofd3DRzpsQNANU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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