SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd50b9ef8812bd48941f4a7cff1373e4fe3aabaed14709d4d847b3e010646d496' 
  AND token = 'ySs4I9KMxSD+qBTVT8bcGS/WGJaliDSRcEdVz8QzyYA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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