SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '51fb02985f74126eec69251b8cb37ea446c42dde6a6a0d2b6e49753e4ef0c870' 
  AND token = 'hNx25y0epLOVDdRNHV0DpE7u7CdRGasCkYO2DtxxEUk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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