SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d6a2eb7aa7f4b956adbbd546eed51901dbbb1e9efd3f41f469057d476100dde' 
  AND token = 'SVeIG6dfniFc/WfsitzaL69HNRE1fxRVsnKNcPQZ7ec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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