SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ce712c9fc90ec4cbda13185641e06e5cd98e0c1f9199420eace67c90ee3c81f5' 
  AND token = 'vOaXsiWbpBF2lLC1cXZ15CXb/vI9ZR6gAwbbLOVwZAE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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