SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'abc9c0bc96c4f917a1cd236f9368d2d733e666d09ffe002fef882d37906421b8' 
  AND token = 'JpFWMP4S+7tRvDZaxp2kwNNb51oj794hF0PMQmrSVV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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