SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70be1fcf0005229f751126e4c3e90d9bca50f35cffb166606be77b7cc5ffc334' 
  AND token = 'KDx88s5/I/umQNK6fcaqK/2LFYPPICNHajklqVGsWxA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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