SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52203d4ec6acbfbe8710940a435147082a419426815b59540a4bbe1ecf3675b7' 
  AND token = 'KcFH3Q9WB3Y2LUiW8siV30nRZsVPeocnAFsNauID71s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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