SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8590ad467609f95b1a954fc044ebb7237e1c1dde11c53e83fae08520321b908' 
  AND token = 'RvATPd+Dh62OyF4L3u8mjKpQvYac5UCZJcyCzGm+VxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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