SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dce7c2274ab8be607f62cb708f287b911053ff1e6955c3a092582cd5c297e936' 
  AND token = 'bKWKyXLR0/vVGihJc4xNnujJrYMCarkNFYfuTykP1Rw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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