SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f59110e840cdd6d56e107ce83e94d77156d001df87d0709bfdae2c3b0d67c798' 
  AND token = '/gE+yEuoyISakiee9YfSPm10OCoLEpYXy9Ysba8fxlQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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