SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c6d7df9f5a7704ed6309f162d89429ddf6a250aa1e03ebfb2a91e7658f1689a5' 
  AND token = 'qJA7areoL18axjMJ7UfMGg2nNSuOQQshG8/o2Ul0bHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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