SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f73d7199a74246eb88afcf0289ccbb30560b6f7263e88a2bfad7a95448c50f98' 
  AND token = 'CyzpiaC+Q43Z7dhdlGWVdtFk9pZ/wtYxbT6xCB9v1So=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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