SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08abeb06978710d1bd9fc0d9188be22e498435546bb0c94c91006e381546f646' 
  AND token = 'dWUjwygt6yt90pVnDOFwCvsAJHJNvVe6x3WRzmqwKio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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