SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7284342b3aa9936c2b4a0d86c7996830de80db9eea0a03b83fe5eff02563f815' 
  AND token = 'xwUx0VPFTI7+2gqLZRUK4hBnhCs8XARJPUvuy5bgtk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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