SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '16cb79114e530592f4f79cdf3d65350f4dccd828f0655d6ac1d60ba99d121b6b' 
  AND token = 'kjvYUcuqZzra8e8EZPECK2HG3HBNeUIEkEUxt+j7Hug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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