SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '784150a2b45634f5c519057bfa51bf3008ab97bc1bc5d8bdfc219965cc43313e' 
  AND token = 'LP60G3Mlr6SFUIfSTcmnutZn24Lq8UTFknjaNWbGB2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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