SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '42fb49f5318d8412f92c263101e1f2f7eaaa9bd4896d193aa620bc437c781cf9' 
  AND token = 'gJkCuDi//cuDB3vEGEW2BLPuOF+wKUgtU9lHlM1Nrcs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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