SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56f0078514e4449089ffade97df7c6b7c7b9172e1a3665f74a224c9dc1c4c95d' 
  AND token = 'h/Zrw1JVSZVSXBEPuXv4Jo6C5JGigd6Sv+Cb7XAPJ7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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