SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c28d3ea7965582b894640ad2539e5bcb24bee627955bdc4a7c2c0fe270cc83af' 
  AND token = 'GBH8WrSV+3vV9Xl00EWnLVDAKRSJCrHmoYUaUEPJEvk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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