SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d525888fe7dbfa21574a3394616d56db634ed9854117fefaa39d5dc2104ee47' 
  AND token = 'elvixImz22HtHxGFTt7CLecJCfzgg+Kxaxzj6BQIsME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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