SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71b5e97ab6d3390bc5f02089f2b98d51d436dbc47770b9f55d022b1b7ad447b0' 
  AND token = 'OyXwIi86BIgPuPHqIC040Yk7LJjtABinKeAFzJLZIvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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