SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '88ef7e2867b5937c47e69714be0fafe3fd6692a1a3a2dc19e0a6370f65daf347' 
  AND token = 'QHng8oQTp8GMIWA59mSPigBECKBGPILggw37IeVw3FA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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