SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2df205ee103f46dfaab86e5faf6104eeab841d2d8cef8676521d71a241d0bc43' 
  AND token = 'pPXFiyMOAomEUQS0jRPTvbSuZpTaBW8LMp3IDCdOvs8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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