SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f0a6c64599032ce70dede6f0811fee2fbe84e36eaa8c646d34b96c448e49b57' 
  AND token = '2T7dnwvcq13dxXH+VREwMBsOc+J56FX2eCqHyq9NGzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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